Self-centering chuck.



L. N. BRUNER. SELF CENTERING CHUCK.

APPLICATION FILED OCT.25,1913- I 1,1 @,3% Patented Apr. 18, 1916.

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SELF CENTERING CHUCK.

APPLICATION FILED 00125, 1913.

Patented Apr. 18, 1916.

3 SHEETS-SHEET 2- vL. N. BRUNER'.

SELF CENTERING CHUCK." APPLICATION FILED OCT- 25, 1913.

Patented Apr. 18, 1916.

3 SHEETSSHEET 3.

Warnyi,

LOUIS NAGLEE BRUNER, 0F ZURICH, SWITZERLAND.

SELF-CENTERING CHUCK.

Specification of Letters Patent.

Patented Apr. 15%, rare.

Application filed October 25, 1913. Serial No. 797,334.

1 0 all to 7mm it may concern Be it known that 1, Louis NAGLEE Barman, a citizen of the United States, residing at 7 Bellerivestrasse, Zurich, Switzerland, have invented a certain new and useful Self-Centering Chuck, of which the following is a specification.

This invention has reference to an improved self-centering chuck designed chiefly for use in bottle manufacture, in the grinding of the mouths of stoppered bottles. The main purpose of the invention is to enable the interior surface or bore of the article, such as a bottle mouth, to be centered exactly in a machine for grinding the same (ready to receive the stopper, for instance) in spite of the fact that the outer surface thereof may not perhaps be concentric with the inner surface, so that merely clamping it around the outside (as in an ordinary selfcentering chuck), would not suflice.

The invention is applicable however to various purposes where an opening or hole in an article is to be centered properly for the purpose of being ground, turned, or otherwise finished.

According to the invention the chuck is provided with a loose seating plate having a conical aperture or an aperture with a conical or inclined edge, to receive the work, the purpose of being ground, turned, or such as the outer lip or edge of the bottle mouth (or other article). Means are also provided to bring the interior of the mouth or opening exactly into a central position when the outer part of the lip or edge thereof is resting in the seating plate.

The bottle or other piece of work being pushed into the conical cavity in the seating plate, the inner edge of its mouth or aperture is engaged or acted on by the centering means or device, and the said mouth or aperture is thereby brought exactly into the required position. During this operating if the outer edge of the mouth or aperture is not already concentric, the seating plate becomes displaced, more or less, transversely to the axis. Suitable arrangements are also provided whereby the parts are firmly clamped in this position, on the centering means or device being withdrawn, leaving the mouth or aperture clear for the entrance of the grinding or finishing tool.

The centering means may, for example, comprise three hook-like centering fingers or prongs which can be caused to move inward and outward in unison and to project into the mouth of the bottle. The tips of these fingers have their inner surfaces (which constltute the actual centering devices) all inclined at the same angle to the axis of rotation, so that in effect they practically form parts of the surface of a cone. In fact, in stead of having three prongs, a conical or tapered centering piece carried by a single arm, may also be employed as will be herebeinafter described and this tape "ed piece or plug may be approximately triangular or three-cornered in cross-section, to facilitate the centralizing action.

In order that the invention may be clearly understood and readily carried into efledt reference will now be had to the accompanymg drawings, in which Figure 1 is a vertical central section of a form of the improved chuck in which the self-centering means comprises three pivoted prongs. Fig. 2 is a front view of the same, but with the outer casing removed. Fig. 8 is a vertical central section of a modified arrangement in which a single arm with a cone-piece is employed, as the centering means. Fig. 4 is an elevation of Fig. 3 as seen from the left.

Referring now particularly to the example shown in Figs. 1 and 2, the chuck comprises an outer cylindrical shell or body a screw-threaded externally to fit in a suitable holder such for instance as the outer casing a The said shell a is provided with an inwardly projecting flange 7) at its front end.

0 is the seating plate, which has a conical central cavity or aperture (Z and rests against the interior of the flange Z2. Behind the seating plate is a ring 6 carrying the pivots or hinge pins f of the three hook-like centering prongs g the tips h of which pro ject backwardly in an inclined direction into the said aperture, mouth or cavity (Z in the seating plate. Suitable cushioning springs 71 may be situated in holes j in the seating plate, and are arranged to bear against the pivot ring e to steady its seating plate.

The prongs g each have, near their pivots, a small projection or heel Jr; which forms with the main part of the prong an arrangement resembling a bell-crank lever, the

projections or heels being in fact the short .11.

arms of the levers. These projections or heels in engage in an annular groove Z inside the shell or body of the chuck, so that when.

the pivot ring 6 is moved or pressed sidewise in the chuck, theprongs are caused to swing radially on their pivots owing to the fact that the heels or projections (being engaged in the annular groove) cannot follow the sidewise movement. To effect such a sidewise movement of the pivot ring 6, a flanged ring or annular cap on is screwed into the rear of the shell and presses against one side of the said pivot ring, this cap having an enlarged outer flange by which it can be grasped and turned one way or the other.

- The operation is as follows :The article to be centered, such as the mouth of the bottle 0 is inserted into the chuck from behind, so that the outer edge of said mouth presses into the conical aperture d in the seating plate 0, while the inner edge of the mouth rests on the inclined tips h of the threecentering prongs g. The guiding action of the latter therefore brings the axis of the interior surface of the bottle mouth exactly coincident with the axis of revolution or practically so. Should the outer surface not be true, any inequality is allowed for by the seating plate yielding and sliding a little in a transverse direction to adjust itself to such inequality. After this the screw cap m is screwed inward and forces the pivot ring '0 forward, thereby causing the prongs g to swing radially outward clear of the bottle-mouth. In this movement the ring 6 also ultimately becomes pressed against and jams the pivot ring tightly against the seating plate so looking the latter and thereby the bottle mouth (in the tapering aperture d) firmly in the desired position.

It will be readily understood that the bottle is in practice kept pressed forward tightly against the seating plate by a powerful spring forming an ordinary part of the grinding machine, and therefore not shown in the drawing.

In the example shown in Figs. 3 and 4, a somewhat simpler construction is adopted, the centering means consisting of a tapering or conical plug k carried by a single arm 9 pivoted at f on any convenient adjacent part 7) of the machine, so that it can be turned by its handle 9 either into the position in which it thrusts the plug into the bottle mouth 0 or it can be turned back on its pivot f entirely out of the way. The plug 12, may be either circular in section or it may as shown have a triangular section,

the three edges which may be flattened (at the angles) serving to assist the centralizing action. In either case a groove or channel k is formed in its upper side, to permit it, as it is swung into and out of position, to clear the point of the grinding pencil q in the case of a bottle-mouth grinding machine. This grinding pencil is carried in the known way (forming no part of the present invention) and in the position shown is ready to be moved forward into the bottle month. In its general respect the arrangement resembles that in Figs. 1 and 2, the seating plate 0 being situated inside the ring a so that it can adjust itself against the flange 6 thereof exactly as before. The said ring a screws into a casing a and the screw-cap m works in the same piece a The springs i used in the former arrangement are however dispensed with, a plain intermediate ring or washer e being interposed between the screw cap 022, and the seating plate 0, while the cap is provided with a pair of handles a on an outer collar 72 for operating it more easily.

WV hat I claim as my invention and desire to secure by Letters Patent of the United States is 1. A self-centering chuck comprising a seating plate for the article to be centered, means for supporting said plate so that it can move transversely under the action of the article as the latter seats itself, and means for bringing the article exactly into the central position after it is seated in the transverse plate, substantially as described.

2. A self-centering chuck comprising a seating plate, means for clamping and releasing said plate, a conical mouth on one side of said plate to receive the article, and self centering means adapted to project through the plate from the other side and engage the interior of the article substantially as described.

3. A self-centering chuck comprising a seating plate, means for clamping said plate in its adjusted position, a conical mouth on one side of said plate to receive the article, a tapered plug adapted to centralize said article from the other side thereof, and a pivoted arm carrying said tapered plug, substantially as described.

In witness whereof I afiix my signature in presence of two witnesses.

LOUIS NAGLEE BRUNER. lVitnesses JAMES DADE, THOMAS B. Krrsox.

copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). C." 

